Modern surface mining shovels are very large and complicated equipment for digging, lifting, moving and depositing the material being mined. The various major assemblies of the shovels such as the crawler propel system, the swinging upper frame and body assembly, and the handle and dipper which are mounted for pivotal and crowd movement on the boom, are commonly driven by electric motor and gear transmission systems. Due to the need for variable speed and relatively accurate positioning of these various assemblies, the electric motors used are typically D.C. motors. The transmission systems for each of these assemblies include a variety of shafts, gears and pinion gears.
The swing drive systems for shovels are typically mounted on the upper frame and consist of several D.C. motors each driving, through a transmission for each of the motors, pinion gears extending downward from the upper frame. Each of the pinion gears engage a large swing gear mounted on a lower frame or car body which is moved along the ground by a propel system driving a continuous crawler track. The swing drives rotate or swing the upper frame on the car body which is stationary relative to the upper frame. The entire swing drive system is complex and its cost and weight contribute significantly to the overall cost and weight of the machine. There has been a long standing effort by shovel manufacturers to somehow simplify and reduce the cost and weight of swing systems.
A more recent problem relates to the high level of lubrication required by the swing system. The lubricants used in the swing system fall or drip from the various gears and shafts and this spillage of lubricant has become an environmental issue at many mines where shovels are in use.
The improved swing system of the invention disclosed herein is intended to decrease the weight and cost of the swing system and minimize the need for lubricants such as now used in swing drives.